1. Field of the Invention
The present invention relates to a liquid crystal display apparatus.
2. Description of the Related Art
Generally a display apparatus using liquid crystal or the like is equipment for outputting image information, and it may also receive input information such as an image with the addition of an optical input function. This technology enables input/output of information and bidirectional exchange of information with a single device.
By using a liquid crystal display element provided with an optical input function, a fingerprint can be read by pressing a finger against a liquid crystal display panel, or a document may be pressed onto the liquid crystal display panel to read characters written thereon. Because a position which is touched with the finger or a pen on the display panel can be read optically, the liquid crystal display apparatus can be provided with the same function as a touch panel. Generally, although the display apparatus using liquid crystal or the like is equipment for outputting image information, it may also receive input information such as an image with the addition of the optical input function. This technology enables input/output of information or bidirectional exchange of information with a single device (Jpn. Pat. Appln. KOKAI Publication No. 2001-292276).
To achieve the touch panel function, upon start of read, a video displayed up to then is changed over to a read video for reading a target image. Because the read video needs to be a video which does not affect the reading of the image, it is, for example, an image in which a single color, for example, blue is displayed uniformly. Then, light from a light source such as a backlight BL is temporarily irradiated onto a document or the like on the liquid crystal display panel via the displayed read video. Then, light reflected from the document or the like is detected within the liquid crystal display panel and processed so as to read an image.
With the read video displayed, its information is read and then, display of the display video is restarted as required.
Therefore, in the conventional method, display of image information needs to be stopped temporarily for reading and then the display screen needs to be changed to such a read screen. Consequently, if it takes about several seconds to read any image, the display of image information is stopped in this time.